1. Field of the Invention
The invention relates generally to an apparatus for delivering fuel to an engine and more particularly to a mechanical fuel pumping apparatus with internal pressure regulation.
2. Description of Related Art
Mechanical fuel pumps in current use do not have internal pressure regulation. The fuel pressure varies for different engine operating points, being high at idle and dropping low at higher speed/load operating points. Also, during a transient event, i.e. the throttle transitions from open position to closed position, the fuel pressure spikes. This spike can cause excess fuel delivery to the engine. This is undesirable, as a rich fuel/air mixture causes the engine to operate in a non-optimal condition which effects vehicle drivability. These pressure fluctuations have been addressed using an external pressure regulator added in line between the fuel pump and the fuel/air mixer (such as a carburetor), but the external fuel pressure regulator adds to assembly complexity, parts cost, and engine compartment clutter.
It would be advantageous to provide a mechanical fuel pump with internal pressure regulation to eliminate these issues of assembly complexity and engine compartment clutter.